1/* Definitions of floating-point access for GNU compiler.
2 Copyright (C) 1989-2023 Free Software Foundation, Inc.
3
4 This file is part of GCC.
5
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 3, or (at your option) any later
9 version.
10
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
19
20#ifndef GCC_REAL_H
21#define GCC_REAL_H
22
23/* An expanded form of the represented number. */
24
25/* Enumerate the special cases of numbers that we encounter. */
26enum real_value_class {
27 rvc_zero,
28 rvc_normal,
29 rvc_inf,
30 rvc_nan
31};
32
33#define SIGNIFICAND_BITS (128 + HOST_BITS_PER_LONG)
34#define EXP_BITS (32 - 6)
35#define MAX_EXP ((1 << (EXP_BITS - 1)) - 1)
36#define SIGSZ (SIGNIFICAND_BITS / HOST_BITS_PER_LONG)
37#define SIG_MSB ((unsigned long)1 << (HOST_BITS_PER_LONG - 1))
38
39struct GTY(()) real_value {
40 /* Use the same underlying type for all bit-fields, so as to make
41 sure they're packed together, otherwise REAL_VALUE_TYPE_SIZE will
42 be miscomputed. */
43 unsigned int /* ENUM_BITFIELD (real_value_class) */ cl : 2;
44 /* 1 if number is decimal floating point. */
45 unsigned int decimal : 1;
46 /* 1 if number is negative. */
47 unsigned int sign : 1;
48 /* 1 if number is signalling. */
49 unsigned int signalling : 1;
50 /* 1 if number is canonical
51 All are generally used for handling cases in real.cc. */
52 unsigned int canonical : 1;
53 /* unbiased exponent of the number. */
54 unsigned int uexp : EXP_BITS;
55 /* significand of the number. */
56 unsigned long sig[SIGSZ];
57};
58
59#define REAL_EXP(REAL) \
60 ((int)((REAL)->uexp ^ (unsigned int)(1 << (EXP_BITS - 1))) \
61 - (1 << (EXP_BITS - 1)))
62#define SET_REAL_EXP(REAL, EXP) \
63 ((REAL)->uexp = ((unsigned int)(EXP) & (unsigned int)((1 << EXP_BITS) - 1)))
64
65/* Various headers condition prototypes on #ifdef REAL_VALUE_TYPE, so it
66 needs to be a macro. We do need to continue to have a structure tag
67 so that other headers can forward declare it. */
68#define REAL_VALUE_TYPE struct real_value
69
70/* We store a REAL_VALUE_TYPE into an rtx, and we do this by putting it in
71 consecutive "w" slots. Moreover, we've got to compute the number of "w"
72 slots at preprocessor time, which means we can't use sizeof. Guess. */
73
74#define REAL_VALUE_TYPE_SIZE (SIGNIFICAND_BITS + 32)
75#define REAL_WIDTH \
76 (REAL_VALUE_TYPE_SIZE/HOST_BITS_PER_WIDE_INT \
77 + (REAL_VALUE_TYPE_SIZE%HOST_BITS_PER_WIDE_INT ? 1 : 0)) /* round up */
78
79/* Verify the guess. */
80extern char test_real_width
81 [sizeof (REAL_VALUE_TYPE) <= REAL_WIDTH * sizeof (HOST_WIDE_INT) ? 1 : -1];
82
83/* Calculate the format for CONST_DOUBLE. We need as many slots as
84 are necessary to overlay a REAL_VALUE_TYPE on them. This could be
85 as many as four (32-bit HOST_WIDE_INT, 128-bit REAL_VALUE_TYPE).
86
87 A number of places assume that there are always at least two 'w'
88 slots in a CONST_DOUBLE, so we provide them even if one would suffice. */
89
90#if REAL_WIDTH == 1
91# define CONST_DOUBLE_FORMAT "ww"
92#else
93# if REAL_WIDTH == 2
94# define CONST_DOUBLE_FORMAT "ww"
95# else
96# if REAL_WIDTH == 3
97# define CONST_DOUBLE_FORMAT "www"
98# else
99# if REAL_WIDTH == 4
100# define CONST_DOUBLE_FORMAT "wwww"
101# else
102# if REAL_WIDTH == 5
103# define CONST_DOUBLE_FORMAT "wwwww"
104# else
105# if REAL_WIDTH == 6
106# define CONST_DOUBLE_FORMAT "wwwwww"
107# else
108 #error "REAL_WIDTH > 6 not supported"
109# endif
110# endif
111# endif
112# endif
113# endif
114#endif
115
116
117/* Describes the properties of the specific target format in use. */
118struct real_format
119{
120 /* Move to and from the target bytes. */
121 void (*encode) (const struct real_format *, long *,
122 const REAL_VALUE_TYPE *);
123 void (*decode) (const struct real_format *, REAL_VALUE_TYPE *,
124 const long *);
125
126 /* The radix of the exponent and digits of the significand. */
127 int b;
128
129 /* Size of the significand in digits of radix B. */
130 int p;
131
132 /* Size of the significant of a NaN, in digits of radix B. */
133 int pnan;
134
135 /* The minimum negative integer, x, such that b**(x-1) is normalized. */
136 int emin;
137
138 /* The maximum integer, x, such that b**(x-1) is representable. */
139 int emax;
140
141 /* The bit position of the sign bit, for determining whether a value
142 is positive/negative, or -1 for a complex encoding. */
143 int signbit_ro;
144
145 /* The bit position of the sign bit, for changing the sign of a number,
146 or -1 for a complex encoding. */
147 int signbit_rw;
148
149 /* If this is an IEEE interchange format, the number of bits in the
150 format; otherwise, if it is an IEEE extended format, one more
151 than the greatest number of bits in an interchange format it
152 extends; otherwise 0. Formats need not follow the IEEE 754-2008
153 recommended practice regarding how signaling NaNs are identified,
154 and may vary in the choice of default NaN, but must follow other
155 IEEE practice regarding having NaNs, infinities and subnormal
156 values, and the relation of minimum and maximum exponents, and,
157 for interchange formats, the details of the encoding. */
158 int ieee_bits;
159
160 /* Default rounding mode for operations on this format. */
161 bool round_towards_zero;
162 bool has_sign_dependent_rounding;
163
164 /* Properties of the format. */
165 bool has_nans;
166 bool has_inf;
167 bool has_denorm;
168 bool has_signed_zero;
169 bool qnan_msb_set;
170 bool canonical_nan_lsbs_set;
171 const char *name;
172};
173
174
175/* The target format used for each floating point mode.
176 Float modes are followed by decimal float modes, with entries for
177 float modes indexed by (MODE - first float mode), and entries for
178 decimal float modes indexed by (MODE - first decimal float mode) +
179 the number of float modes. */
180extern const struct real_format *
181 real_format_for_mode[NUM_MODE_FLOAT + NUM_MODE_DECIMAL_FLOAT];
182
183#define REAL_MODE_FORMAT(MODE) \
184 (real_format_for_mode[DECIMAL_FLOAT_MODE_P (MODE) \
185 ? (((MODE) - MIN_MODE_DECIMAL_FLOAT) \
186 + NUM_MODE_FLOAT) \
187 : GET_MODE_CLASS (MODE) == MODE_FLOAT \
188 ? ((MODE) - MIN_MODE_FLOAT) \
189 : (gcc_unreachable (), 0)])
190
191#define FLOAT_MODE_FORMAT(MODE) \
192 (REAL_MODE_FORMAT (as_a <scalar_float_mode> (GET_MODE_INNER (MODE))))
193
194/* The following macro determines whether the floating point format is
195 composite, i.e. may contain non-consecutive mantissa bits, in which
196 case compile-time FP overflow may not model run-time overflow. */
197#define MODE_COMPOSITE_P(MODE) \
198 (FLOAT_MODE_P (MODE) \
199 && FLOAT_MODE_FORMAT (MODE)->pnan < FLOAT_MODE_FORMAT (MODE)->p)
200
201/* Accessor macros for format properties. */
202#define MODE_HAS_NANS(MODE) \
203 (FLOAT_MODE_P (MODE) && FLOAT_MODE_FORMAT (MODE)->has_nans)
204#define MODE_HAS_INFINITIES(MODE) \
205 (FLOAT_MODE_P (MODE) && FLOAT_MODE_FORMAT (MODE)->has_inf)
206#define MODE_HAS_SIGNED_ZEROS(MODE) \
207 (FLOAT_MODE_P (MODE) && FLOAT_MODE_FORMAT (MODE)->has_signed_zero)
208#define MODE_HAS_SIGN_DEPENDENT_ROUNDING(MODE) \
209 (FLOAT_MODE_P (MODE) \
210 && FLOAT_MODE_FORMAT (MODE)->has_sign_dependent_rounding)
211
212/* This class allows functions in this file to accept a floating-point
213 format as either a mode or an explicit real_format pointer. In the
214 former case the mode must be VOIDmode (which means "no particular
215 format") or must satisfy SCALAR_FLOAT_MODE_P. */
216class format_helper
217{
218public:
219 format_helper (const real_format *format) : m_format (format) {}
220 template<typename T> format_helper (const T &);
221 const real_format *operator-> () const { return m_format; }
222 operator const real_format *() const { return m_format; }
223
224 bool decimal_p () const { return m_format && m_format->b == 10; }
225 bool can_represent_integral_type_p (tree type) const;
226
227private:
228 const real_format *m_format;
229};
230
231template<typename T>
232inline format_helper::format_helper (const T &m)
233 : m_format (m == VOIDmode ? 0 : REAL_MODE_FORMAT (m))
234{}
235
236/* Declare functions in real.cc. */
237
238/* True if the given mode has a NaN representation and the treatment of
239 NaN operands is important. Certain optimizations, such as folding
240 x * 0 into 0, are not correct for NaN operands, and are normally
241 disabled for modes with NaNs. The user can ask for them to be
242 done anyway using the -funsafe-math-optimizations switch. */
243extern bool HONOR_NANS (machine_mode);
244extern bool HONOR_NANS (const_tree);
245extern bool HONOR_NANS (const_rtx);
246
247/* Like HONOR_NANs, but true if we honor signaling NaNs (or sNaNs). */
248extern bool HONOR_SNANS (machine_mode);
249extern bool HONOR_SNANS (const_tree);
250extern bool HONOR_SNANS (const_rtx);
251
252/* As for HONOR_NANS, but true if the mode can represent infinity and
253 the treatment of infinite values is important. */
254extern bool HONOR_INFINITIES (machine_mode);
255extern bool HONOR_INFINITIES (const_tree);
256extern bool HONOR_INFINITIES (const_rtx);
257
258/* Like HONOR_NANS, but true if the given mode distinguishes between
259 positive and negative zero, and the sign of zero is important. */
260extern bool HONOR_SIGNED_ZEROS (machine_mode);
261extern bool HONOR_SIGNED_ZEROS (const_tree);
262extern bool HONOR_SIGNED_ZEROS (const_rtx);
263
264/* Like HONOR_NANS, but true if given mode supports sign-dependent rounding,
265 and the rounding mode is important. */
266extern bool HONOR_SIGN_DEPENDENT_ROUNDING (machine_mode);
267extern bool HONOR_SIGN_DEPENDENT_ROUNDING (const_tree);
268extern bool HONOR_SIGN_DEPENDENT_ROUNDING (const_rtx);
269
270/* Binary or unary arithmetic on tree_code. */
271extern bool real_arithmetic (REAL_VALUE_TYPE *, int, const REAL_VALUE_TYPE *,
272 const REAL_VALUE_TYPE *);
273
274/* Compare reals by tree_code. */
275extern bool real_compare (int, const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
276
277/* Determine whether a floating-point value X is infinite. */
278extern bool real_isinf (const REAL_VALUE_TYPE *);
279
280/* Determine whether a floating-point value X is infinite with SIGN. */
281extern bool real_isinf (const REAL_VALUE_TYPE *, bool sign);
282
283/* Determine whether a floating-point value X is a NaN. */
284extern bool real_isnan (const REAL_VALUE_TYPE *);
285
286/* Determine whether a floating-point value X is a signaling NaN. */
287extern bool real_issignaling_nan (const REAL_VALUE_TYPE *);
288
289/* Determine whether floating-point value R is a denormal. This
290 function is only valid for normalized values. */
291inline bool
292real_isdenormal (const REAL_VALUE_TYPE *r, machine_mode mode)
293{
294 return r->cl == rvc_normal && REAL_EXP (r) < REAL_MODE_FORMAT (mode)->emin;
295}
296
297/* Determine whether a floating-point value X is finite. */
298extern bool real_isfinite (const REAL_VALUE_TYPE *);
299
300/* Determine whether a floating-point value X is negative. */
301extern bool real_isneg (const REAL_VALUE_TYPE *);
302
303/* Determine whether a floating-point value X is minus zero. */
304extern bool real_isnegzero (const REAL_VALUE_TYPE *);
305
306/* Determine whether a floating-point value X is plus or minus zero. */
307extern bool real_iszero (const REAL_VALUE_TYPE *);
308
309/* Determine whether a floating-point value X is zero with SIGN. */
310extern bool real_iszero (const REAL_VALUE_TYPE *, bool sign);
311
312/* Test relationships between reals. */
313extern bool real_identical (const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
314extern bool real_equal (const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
315extern bool real_less (const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
316
317/* Extend or truncate to a new format. */
318extern void real_convert (REAL_VALUE_TYPE *, format_helper,
319 const REAL_VALUE_TYPE *);
320
321/* Return true if truncating to NEW is exact. */
322extern bool exact_real_truncate (format_helper, const REAL_VALUE_TYPE *);
323
324/* Render R as a decimal floating point constant. */
325extern void real_to_decimal (char *, const REAL_VALUE_TYPE *, size_t,
326 size_t, int);
327
328/* Render R as a decimal floating point constant, rounded so as to be
329 parsed back to the same value when interpreted in mode MODE. */
330extern void real_to_decimal_for_mode (char *, const REAL_VALUE_TYPE *, size_t,
331 size_t, int, machine_mode);
332
333/* Render R as a hexadecimal floating point constant. */
334extern void real_to_hexadecimal (char *, const REAL_VALUE_TYPE *,
335 size_t, size_t, int);
336
337/* Render R as an integer. */
338extern HOST_WIDE_INT real_to_integer (const REAL_VALUE_TYPE *);
339
340/* Initialize R from a decimal or hexadecimal string. Return -1 if
341 the value underflows, +1 if overflows, and 0 otherwise. */
342extern int real_from_string (REAL_VALUE_TYPE *, const char *);
343/* Wrapper to allow different internal representation for decimal floats. */
344extern void real_from_string3 (REAL_VALUE_TYPE *, const char *, format_helper);
345
346extern long real_to_target (long *, const REAL_VALUE_TYPE *, format_helper);
347
348extern void real_from_target (REAL_VALUE_TYPE *, const long *,
349 format_helper);
350
351extern void real_inf (REAL_VALUE_TYPE *, bool sign = false);
352
353extern bool real_nan (REAL_VALUE_TYPE *, const char *, int, format_helper);
354
355extern void real_maxval (REAL_VALUE_TYPE *, int, machine_mode);
356
357extern void real_2expN (REAL_VALUE_TYPE *, int, format_helper);
358
359extern unsigned int real_hash (const REAL_VALUE_TYPE *);
360
361
362/* Target formats defined in real.cc. */
363extern const struct real_format ieee_single_format;
364extern const struct real_format mips_single_format;
365extern const struct real_format motorola_single_format;
366extern const struct real_format spu_single_format;
367extern const struct real_format ieee_double_format;
368extern const struct real_format mips_double_format;
369extern const struct real_format motorola_double_format;
370extern const struct real_format ieee_extended_motorola_format;
371extern const struct real_format ieee_extended_intel_96_format;
372extern const struct real_format ieee_extended_intel_96_round_53_format;
373extern const struct real_format ieee_extended_intel_128_format;
374extern const struct real_format ibm_extended_format;
375extern const struct real_format mips_extended_format;
376extern const struct real_format ieee_quad_format;
377extern const struct real_format mips_quad_format;
378extern const struct real_format vax_f_format;
379extern const struct real_format vax_d_format;
380extern const struct real_format vax_g_format;
381extern const struct real_format real_internal_format;
382extern const struct real_format decimal_single_format;
383extern const struct real_format decimal_double_format;
384extern const struct real_format decimal_quad_format;
385extern const struct real_format ieee_half_format;
386extern const struct real_format arm_half_format;
387extern const struct real_format arm_bfloat_half_format;
388
389
390/* ====================================================================== */
391/* Crap. */
392
393/* Determine whether a floating-point value X is infinite. */
394#define REAL_VALUE_ISINF(x) real_isinf (&(x))
395
396/* Determine whether a floating-point value X is a NaN. */
397#define REAL_VALUE_ISNAN(x) real_isnan (&(x))
398
399/* Determine whether a floating-point value X is a signaling NaN. */
400#define REAL_VALUE_ISSIGNALING_NAN(x) real_issignaling_nan (&(x))
401
402/* Determine whether a floating-point value X is negative. */
403#define REAL_VALUE_NEGATIVE(x) real_isneg (&(x))
404
405/* Determine whether a floating-point value X is minus zero. */
406#define REAL_VALUE_MINUS_ZERO(x) real_isnegzero (&(x))
407
408/* IN is a REAL_VALUE_TYPE. OUT is an array of longs. */
409#define REAL_VALUE_TO_TARGET_LONG_DOUBLE(IN, OUT) \
410 real_to_target (OUT, &(IN), \
411 float_mode_for_size (LONG_DOUBLE_TYPE_SIZE).require ())
412
413#define REAL_VALUE_TO_TARGET_DOUBLE(IN, OUT) \
414 real_to_target (OUT, &(IN), float_mode_for_size (64).require ())
415
416/* IN is a REAL_VALUE_TYPE. OUT is a long. */
417#define REAL_VALUE_TO_TARGET_SINGLE(IN, OUT) \
418 ((OUT) = real_to_target (NULL, &(IN), float_mode_for_size (32).require ()))
419
420/* Real values to IEEE 754 decimal floats. */
421
422/* IN is a REAL_VALUE_TYPE. OUT is an array of longs. */
423#define REAL_VALUE_TO_TARGET_DECIMAL128(IN, OUT) \
424 real_to_target (OUT, &(IN), decimal_float_mode_for_size (128).require ())
425
426#define REAL_VALUE_TO_TARGET_DECIMAL64(IN, OUT) \
427 real_to_target (OUT, &(IN), decimal_float_mode_for_size (64).require ())
428
429/* IN is a REAL_VALUE_TYPE. OUT is a long. */
430#define REAL_VALUE_TO_TARGET_DECIMAL32(IN, OUT) \
431 ((OUT) = real_to_target (NULL, &(IN), \
432 decimal_float_mode_for_size (32).require ()))
433
434extern REAL_VALUE_TYPE real_value_truncate (format_helper, REAL_VALUE_TYPE);
435
436extern REAL_VALUE_TYPE real_value_negate (const REAL_VALUE_TYPE *);
437extern REAL_VALUE_TYPE real_value_abs (const REAL_VALUE_TYPE *);
438
439extern int significand_size (format_helper);
440
441extern REAL_VALUE_TYPE real_from_string2 (const char *, format_helper);
442
443#define REAL_VALUE_ATOF(s, m) \
444 real_from_string2 (s, m)
445
446#define CONST_DOUBLE_ATOF(s, m) \
447 const_double_from_real_value (real_from_string2 (s, m), m)
448
449#define REAL_VALUE_FIX(r) \
450 real_to_integer (&(r))
451
452/* ??? Not quite right. */
453#define REAL_VALUE_UNSIGNED_FIX(r) \
454 real_to_integer (&(r))
455
456/* ??? These were added for Paranoia support. */
457
458/* Return floor log2(R). */
459extern int real_exponent (const REAL_VALUE_TYPE *);
460
461/* R = A * 2**EXP. */
462extern void real_ldexp (REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *, int);
463
464/* **** End of software floating point emulator interface macros **** */
465
466/* Constant real values 0, 1, 2, -1 and 0.5. */
467
468extern REAL_VALUE_TYPE dconst0;
469extern REAL_VALUE_TYPE dconst1;
470extern REAL_VALUE_TYPE dconst2;
471extern REAL_VALUE_TYPE dconstm0;
472extern REAL_VALUE_TYPE dconstm1;
473extern REAL_VALUE_TYPE dconsthalf;
474extern REAL_VALUE_TYPE dconstinf;
475extern REAL_VALUE_TYPE dconstninf;
476
477#define dconst_e() (*dconst_e_ptr ())
478#define dconst_third() (*dconst_third_ptr ())
479#define dconst_quarter() (*dconst_quarter_ptr ())
480#define dconst_sixth() (*dconst_sixth_ptr ())
481#define dconst_ninth() (*dconst_ninth_ptr ())
482#define dconst_sqrt2() (*dconst_sqrt2_ptr ())
483#define dconst_pi() (*dconst_pi_ptr ())
484
485/* Function to return the real value special constant 'e'. */
486extern const REAL_VALUE_TYPE *dconst_e_ptr (void);
487
488/* Function to return the real value special constant 'pi'. */
489extern const REAL_VALUE_TYPE *dconst_pi_ptr (void);
490
491/* Returns a cached REAL_VALUE_TYPE corresponding to 1/n, for various n. */
492extern const REAL_VALUE_TYPE *dconst_third_ptr (void);
493extern const REAL_VALUE_TYPE *dconst_quarter_ptr (void);
494extern const REAL_VALUE_TYPE *dconst_sixth_ptr (void);
495extern const REAL_VALUE_TYPE *dconst_ninth_ptr (void);
496
497/* Returns the special REAL_VALUE_TYPE corresponding to sqrt(2). */
498extern const REAL_VALUE_TYPE * dconst_sqrt2_ptr (void);
499
500/* Function to return a real value (not a tree node)
501 from a given integer constant. */
502REAL_VALUE_TYPE real_value_from_int_cst (const_tree, const_tree);
503
504/* Return a CONST_DOUBLE with value R and mode M. */
505extern rtx const_double_from_real_value (REAL_VALUE_TYPE, machine_mode);
506
507/* Replace R by 1/R in the given format, if the result is exact. */
508extern bool exact_real_inverse (format_helper, REAL_VALUE_TYPE *);
509
510/* Return true if arithmetic on values in IMODE that were promoted
511 from values in TMODE is equivalent to direct arithmetic on values
512 in TMODE. */
513bool real_can_shorten_arithmetic (machine_mode, machine_mode);
514
515/* In tree.cc: wrap up a REAL_VALUE_TYPE in a tree node. */
516extern tree build_real (tree, REAL_VALUE_TYPE);
517
518/* Likewise, but first truncate the value to the type. */
519extern tree build_real_truncate (tree, REAL_VALUE_TYPE);
520
521/* Calculate R as X raised to the integer exponent N in format FMT. */
522extern bool real_powi (REAL_VALUE_TYPE *, format_helper,
523 const REAL_VALUE_TYPE *, HOST_WIDE_INT);
524
525/* Standard round to integer value functions. */
526extern void real_trunc (REAL_VALUE_TYPE *, format_helper,
527 const REAL_VALUE_TYPE *);
528extern void real_floor (REAL_VALUE_TYPE *, format_helper,
529 const REAL_VALUE_TYPE *);
530extern void real_ceil (REAL_VALUE_TYPE *, format_helper,
531 const REAL_VALUE_TYPE *);
532extern void real_round (REAL_VALUE_TYPE *, format_helper,
533 const REAL_VALUE_TYPE *);
534extern void real_roundeven (REAL_VALUE_TYPE *, format_helper,
535 const REAL_VALUE_TYPE *);
536
537/* Set the sign of R to the sign of X. */
538extern void real_copysign (REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
539
540/* Check whether the real constant value given is an integer. */
541extern bool real_isinteger (const REAL_VALUE_TYPE *, format_helper);
542extern bool real_isinteger (const REAL_VALUE_TYPE *, HOST_WIDE_INT *);
543
544/* Calculate nextafter (X, Y) in format FMT. */
545extern bool real_nextafter (REAL_VALUE_TYPE *, format_helper,
546 const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
547
548/* Write into BUF the maximum representable finite floating-point
549 number, (1 - b**-p) * b**emax for a given FP format FMT as a hex
550 float string. BUF must be large enough to contain the result. */
551extern void get_max_float (const struct real_format *, char *, size_t, bool);
552
553#ifndef GENERATOR_FILE
554/* real related routines. */
555extern wide_int real_to_integer (const REAL_VALUE_TYPE *, bool *, int);
556extern void real_from_integer (REAL_VALUE_TYPE *, format_helper,
557 const wide_int_ref &, signop);
558#endif
559
560/* Fills r with the largest value such that 1 + r*r won't overflow.
561 This is used in both sin (atan (x)) and cos (atan(x)) optimizations. */
562extern void build_sinatan_real (REAL_VALUE_TYPE *, tree);
563
564#endif /* ! GCC_REAL_H */
565

source code of gcc/real.h